Shuttle positioning means



April 13, 1965 J. PICANOL 3,177,903

SHUTTLE POS ITIONING MEANS Filed July 3, 1962 2 Sheets-Sheet l INVENTOR .lv PICA/VOL BY M 62, 09+ zqfc msars April 13, 1965 J. PICANOL 3,177,903

SHUTTLE POS ITIONING MEANS Filed July 3, 1962 2 Sheets-Sheet 2 INVENTOR .z PICA/VOL BY I e United States Patent "ice 4 Qlaims. is. 139-155) It is well known by all those skilled in the art, that on looms in general, and more particularly on looms of the lift box type, it is most important to keep the speed of the shuttle as low as possible, without impairing the performance of the loom. It is indeed an appreciated advantage, when the shuttle reaches the bottom of its end of travel box with the smallest possible velocity. Hence, the greater the time available for each travel of the shuttle, the lower will be the instantaneous as well as the mean speeds of the latter, so that there will be less danger of breaking the thread, less faults in the finished product and less loom stoppages. Further, on looms with several wefts, or respectively with several colours, it is necessary to take into consideration that the lift box must continual- 1y be displaced so as to bring the corn Jartment corresponding to the shuttle of the weft to be driven, to the level of the shuttle track. It would on the other band also, be favourable if the motion of the boxes were to be made as slow as possible, in order to reduce fatigue as well as any vibrations which might develop. Finally, within the scope of optimum operating conditions of the loom, it would be highly satisfactory if the change in position of the lift box could be brought about at the very moment when the shuttle reaches the end of its travel, so as to have available a maximum of time and hence to be able to reduce the displacement speed of the box. It is however practically impossible to start the motion of the box in such conditions, considering that the extremity of the shuttle is engaged in the picker as soon as aforesaid shuttle comes to the end of its travel, and that it has first to be liberated before the box can be displaced. It is quite obvious that a displacement of the lift box, with the shuttles it contains in each of its compartments, can by no means, be considered before the picker is withdrawn from the path of the adjacent extremities of the shuttles with res ect to the box.

With this purpose in view, it was suggested that such a disengagement should be brought about automatically by conditioning the velocity of the shuttle and by judiciously choosing the materials actually coming into contact with each other, so that the shuttle might rebound slightly on arriving at the end of its travel, thus disengaging itself automatically from the picker. Theoretically such means might seem suitable, but in practice they have to be rejected. It has for instance been found that the conditions of velocity and of materials required to ensure such a rebound of the shuttle cause a greater wear of the picker, considering that in order to rebound, the shuttle will have to reach the end of its travel with considerably increased inertia, without which the rebound will be either impossible or insufficient.

Another disadvantage of the system consists in the great difficulty which is experienced in quantitatively controlling the rebound of the shuttle. 'In the weaving shops where the application of this principle was tried out, the weavers were indeed constantly kept busy, trying to control and to adjust the rebound. Such a preoccupation can but have a detrimental effect upon the efficiency of the loom.

Apparently, the only means of liberating the shuttles before the displacement of the box would consists of a correctly timed withdrawal of the picker, carried out as fast as possible, by means for instance of a properly de- 3,177,903 Patented Apr. 13, 1965 signed and located cam. In practice, however, the problem is quite diiferent because of the considerable efforts encountered, and consequently, the necessity which would arise for such a cam to make use of a roller of relatively large diameter. When drawing a diagram of the movements obtained by such a cam and such a roller acting irectly upon the picking stick, it is found that the elements corresponding to such a diagram are inacceptable in practice.

Moreover, when considering that such a cam should logically be actuated by the driver shaft, the speed of which is half that of the crankshaft, and taking into consideration also the velocity of the shuttle on the track and the speed of displacement of the box, one discovers that only an angular displacement of 4 to 5 of the crankshaft, or 2 to 3 of the cam keyed to the driver shaft, are available for the withdrawal of the picker just before the box is set in motion. This is most definitely insufiicient for a direct control of the picking stick.

Mthough the mechanism according to the present invention is also actuated by the driver shaft, it does perrnit the withdrawal of the picker under optimum conditions and despite the small angular displacement of aforesaid cam. To this purpose however, a mechanism according to the present invention has been fitted between aforesaid cam and the picking stick.

The mechanism substantially consists of a combination of two cams,.the first being keyed to the driver shaft and the second supporting the picking stick, and between these two cams, a mechanical linkage which makes their movements dependent upon each other. The form of the cam which is keyed to the driver shaft is such that it angularly displaces the second cam only during an extremely small own angular displacement, of the order of magnitude, for instance, of 20 The second cam is formed by the appropriate shaping of one of the free ends of a rocker lever.- The mechanical linkage is fitted between the roller which is in cont-act with the first cam and the second free end of aforesaid rocker lever, of which the second cam is an integral part. This mechanical linkage can for instance consist of a second rocker lever, one free end of which carries aforesaid roller which is in contact with the first cam, its other free end being pivotally fixed to the lower end of a rod, the upper end of which is hinged to the second end of aforesaid first rocker lever, of which the second cam is an integral part.

This mechanical linkage is such, that a small angular displacement imparted to the first cam will produce a larger angular displacement of the second cam.

A roller, the pivot pin of which is an integral part of the oscillating stop against which the picking stick rests, is permanently applied against aforesaid second cam by means of an appropriate elastic element. According to one of the characteristics of the present invention, the forms of these two cams are difieernt and designed in such a manner that the displacement of the roller which is in contact with the second cam only takes place during part of the displacement of the roller which is in contact with the first cam. Also, aforesaid displacement of the roller which is applied against the second cam is obtained by an angular displacement of the latter, greater than the corresponding angular displacement of the first cam.

As a result of these various characteristics, the roller which is in contact with the second cam, and respectively the stop of which it is an integral part-and consequently also the picking stick-are displaced almost instantaneously, but however, in such conditions that the contact surfaces between roller and cams are sufi'iciently large to permit the use of rollers of an acceptable diameter and having a surface of sufficient dimensions to warrant normal specific contact pressures.

The more detailed description of this novel mechanism and of its subsidiary arrangements, as given below, will provide a clearer conception of the characteristics of aforesaid mechanism, of effects produced thereby and of the advantages'derived therefrom, reference being made, without anylimitation whatever, to the appended drawings of which:

'Figures -1 and 2 schematically represent two characteristic positions of the withdrawal mechanism according to this invention, respectively the engaged and the disengaged position of the picker;

' Figure 3 shows a curve plotted of the positions of the picker in function of the positions of the crankshaft.

The crankshaft is connected up in the Well known manner .(not shown) to the driver shaft 2 upon which a cam 3 is rigidly fixed. A roller 4, the shaft 5 of which is fixed to one end of a rocker lever 6, is maintained in permanent contact with aforesaid cam 3; rocker lever 6 being capable of oscillating around a pivot pin 7 which is integral with loom frame 8 and moreover subjected to the pull of a retracting spring 9 which actually presses roller 4 against aforesaid earn 3. The other free end of rocker lever 6 is hingedly fixed to one end of a rod 11 by means of pivot pin 10, the other end of which rod is hingedly fixed by means of pivot pin 12 to one of the free ends of a second rocker lever 13. The latter can oscillate around pivot pin 14. This rocker lever 13 is characteristic inasmuch as its second free end is shaped into the form of cam 15. A retracting spring 16 will maintain a roller 17 in permanent contact with cam 15, the shaft .18 of aforesaid roller 17 being integral with mobile stop 19 which is capable of oscillating around fixed pivot pin 20. Picking stick 21, bearing picker 22, is permanently pushed towards aforesaid mobile stop 19 by means of its own well known elastic device (not shown), in the sense of arrow F. Preferably, the hinge joints at the extremities of rod 11 will be completed by ball joints, which is made necessary by the fact that this rod, as well as the parts relating to'its upper end, must necessarily be fitted on the lathe, whilst pivot pin 7 of rocker lever 6 is integral with a fixed part of the frame.

The shape, the relative positions and the dimensions of cam 3, rocker levers 6-13 and their various constituent parts are such that an angular displacement at of first cam 3, corresponding to the withdrawal of picker 22, causes an angular displacement ,8 of the second cam 15, which is greater than angle a. However, this cam has been designed in such a manner that but a small portion of its shaped surface brings about the withdrawal of aforesaid picker.

This cam 15 indeed consists of three zones abc. Zones a and c are cylindrical and concentric with respect topivot pin 14, radius r ofthe first being smaller than.

radius Rof the second, and their difference R-r being greater than the maximum penetration of the shuttle point into picker 22. The slope of zone b is different from the corresponding part b of the form of firm cam 3, inasmuch as within zone b the linear movement of roller 17, which is carried by oscillating stop 19, is different, and respectively greater, than the linear displacement of roller 4 which is in contact with aforementioned part b of first cam 3. As a result of these particular arrangements according to the present invention, it will be seen that during the first and the third parts of the linear displacement of roller 4, roller 17 will remain stationary, as will consequently also aforesaid mobile stop 19, picking stick 21 and picker 22, and that during the second part of linear displacement of roller 4, the subsequent displacement of aforesaid roller 17 and its associated parts 19-21-22 will be much faster than that, during the same period, of aforesaid roller 4.

The operation of this device on a lift box loom would be as follows: when the driver mechanism is at rest, as schematically shown in Figure 1, roller 4 is located at the base of the ramp of cam 3, which is keyed to the driver shaft 2; rod 11 is in its lower position and roller 17 is in contact with cylindrical zone 0 of cam 15, which is the farthest removed from pivoting center 14; oscillating stop 19 is pushed back by means of roller 17 and, in turn, the former solidly holds picking stick 21 in its starting position for a picking operation; picker 22, which is integral with picking stick 21 is in such a position that the tip of adjacent shuttle N is engaged therein. In these circumstances shuttle box B can not be displaced vertically without causing damage to the shuttles as Well as to the picker. In this position also, crankshaft is placed in such a manner that its crank is at its right hand dead center. Aforesaid crankshaftrotates in one direction whilst the lathe is displaced in the opposite direction moving aforesaid shuttle box B along with it.

The crankshaft rotates at double the speed of driver shaft 2, the movement of which is in the sense of arrow F3. During this period, cam 3 pushes back roller 4, which in turn causes rocker lever 13 to oscillate, actuated by rocker lever 6 and rod 11. During the first part of the movement of cam 3, the actual unlocking device remains stationary, because roller 17 merely rests against moving cylindrical zone 0 of second cam 15. Further, if in the diagram of FIGURE 3 the angular displacements of aforesaid cam 15 are taken as ordinates and the corresponding angular. displacements of cam 3, taking into account the ratio due to elements 644-13, are taken as abscissae, it is found that the whole travel along zone a of cam 15, i.e. one third of the total angular travel, or otherwise expressed 10, corresponds to an angular displacement of aforesaid earn 3 which is considerably greater than one third of its total angular displacement during which it moves roller 4.

In the next phase of the angular movement of aforesaid first cam 3, roller 4 continues to be displaced and it will be observed that it is now the shaped zone b of the second cam 15 which comes into contact with roller 17 of, oscillating stop 19, which is itself in permanent contact with picking stick 21. If the angular variations of cam 3 and the corresponding angular variations of cam 15, with respect to'zone b of the latter, are again transferred to the same diagram of FIGURE 3, one discovers that the angular variation of first cam 3 is considerably smaller than one third of the total angular variation for the complete linear displacement of roller 4, this displacement corresponding for instance to an angle of approximately 3 /3 whilst the corresponding angular displacement of cam 15 is about 10.

7 During the third phase of displacement of roller 4, cam 15 is again displaced by 10 so as to complete its oscillation.

It can be concluded, that for a particularly small angular variation of the first cam, which is keyed upon the driver shaft, a considerably larger angular displacement results for the cam actuating the stop, which in turn determines the position of the picking stick 21 and respectively of the picker 22. As a consequence of this extremely small angle of displacement of cam 3 which produces the withdrawal of picker 22, this withdrawal takes place practically instantaneously at the required moment, i.e. at the very instant of a vertical movement of shuttle box B for the purpose of bringing the desired compartment to the level of the shuttle track of the loom.

Hence these arrangements are such, that for an extremely small angular displacement of the driver shaft, the stop which controls the position of the picking stick, and respectively of the picker, remains in contact by its roller, with the control mechanism through surfaces which are of amply sufiicient dimensions to keep the specific pressure within normal and acceptable limits. In consequence of the nature and size of the contact surfaces, one also obtains that, despite the extremely rapid withdrawal motion of the picker, this withdrawal is carried out without rebound and by maintaining a permanent Contact between the various parts considered, namely between cam ing operation, must fit into the cavity of the picker on the picking stick.

It will be sufiicient to make a judicious choice, with respect to the performance of the loom, of the profiles of the cams and, mainly, of the leverage ratios of the elements which make up the mechanical linkage between the two cams. In this manner it becomes possible to control with maximum precision both the time and the speed of the appropriate withdrawal of the picker, as well as the specific pressures on the various elements which are mutually in contact.

It is quite obvious that the present invention is by no means limited to the above described embodiment, it being however understood, that the various elements shown as examples might be replaced by elements which are equivalent or fulfill equivalent functions, in so far as the characteristics'laid down by the present specification are observed.

What I claim is:

1. In a multi-box loom having a shuttle, a vertically movable shuttle box, a picker stick and a picker carried by the picker stick, a mechanism for freeing the picker stick for rearward movement, said mechanism comprising, in combination, a driver shaft, a cam firmly connected with said driver shaft, -a rocker lever, a pivot pin supporting said rocker lever intermediate its ends for oscillatory movement, a roller carried by one end of said rocker lever and engaging said cam, a spring connected with said rocker lever and pressing said roller against said cam, a rod, means pivotally connecting the other end of said rocker lever with one end of said rod, a second rocker lever having a cam-shaped end, means pivotally connecting the other end of the second-mentioned rocker lever with the other end of said rod, a second pivot pin supporting the second-mentioned rocker lever intermediate its ends for oscillatory movement, said camshaped end having a cylindrical surface concentric to the second-mentioned pivot pin, another cylindrical surface concentric to the second-mentioned pivot pin and of small- 6 er radius than that of the first-mentioned cylindrical surface, and a sloping surface extending between the two cylindrical surfaces, a mobile stop adapted to engage said picker stick, another roller carried by said mobile stop and engaging said cam-shaped end, and a spring connected with said mobile stop and pressing the secondmentioned roller against said cam-shaped end, said cam and said cam-shaped end being shaped so that a small angular displacement of said cam gives rise to a larger angular displacement of said cam-shaped end.

2. A mechanism in accordance with claim 1, wherein the cam-shaped end is shaped so that its cylindrical surrface of greater radius is in contact with the secondmentioned roller when the picker stick and the picker are in a waiting position for a pickering operation, the adjacent end of the shuttle being engaged in the picker, the cylindrical surface of smaller radius being in contact with the second-mentioned roller when the picker stick and the picker are in a withdrawn position relatively to the corresponding end of the shuttle during the substantially vertical displacement of the shuttle box.

3. A mechanism in accordance with claim 1, wherein the ratio between the angular displacement of the cam which produces a linear movement of the first-mentioned roller and the corresponding angular displacement of the v cam-shaped end, is at least 3 to 12.

4. A mechanism in accordance with claim 1, wherein the angular displacement of the cam-shaped end which causes picker retraction corresponds to an angular displacement of the cam which is at most /5 of said angular displacement of the cam-shaped end.

References Cited by the Examiner UNITED STATES PATENTS MERVIN STEIN, Primary Examiner.

RUSSELL C. MADER, DONALD W. PARKER,

' Examiners. 

1. IN A MULTI-BOX LOOM HAVING A SHUTTLE, A VERTICALLY MOVABLE SHUTTLE BOX, A PICKER STICK AND A PICKER CARRIED BY THE PICKER STICK, A MECHANISM FOR FREEING THE PICKER STRICK FOR REARWARD MOVEMENT, SAID MECHANISM COMPRISING, IN COMBINATION, A DRIVER SHAFT, A CAM FIRMLY CONNECTED WITH SAID DRIVER SHAFT, A ROCKER LEVER, A PIVOT PIN SUPPORTING SAID ROCKER LEVER INTERMEDIATE ITS ENDS FOR OSCILLATORY MOVEMENT, A ROLLER CARRIED BY ONE END OF SAID ROCKER LEVER AND ENGAGING SAID CAM, A SPRING CONNECTED WITH SAID ROCKER LEVER AND PRESSING SAID ROLLER AGAINST SAID CAM, A ROD, MEANS PIVOTALLY CONNECTING THE OTHER END OF SAID ROCKER LEVER WITH ONE END OF SAID ROD, A SECOND ROCKER LEVER HAVING A CAM-SHAPED END, MEANS PIVOTALLY CONNECTING THE OTHER END OF THE SECOND-MENTIONED ROCKER LEVER WITH THE OTHER END OF SAID ROD, A SECOND PIVOT PIN SUPPORTING THE SECOND-MENTIONED ROCKER LEVER INTERMEDIATE ITS ENDS OF OSCIALLATORY MOVEMENT, SAID CAMSHAPED END HAVING A CYLINDRICAL SURFACE CONCENTRIC TO THE SECOND-MENTIONED PIVOT PIN, ANOTHER CYLINDRICAL SURFACE CONCENTRIC TO THE SECOND-MENTIONED PIVOT PIN AND OF SMALLER RADIUS THAN THAT OF THE FIRST-MENTIONED CYLINDRICAL SURFACE, AND A SLOPING SURFACE EXTENDING BETWEEN THE TWO CYLINDRICAL SURFACES, A MOBILE STOP ADAPTED TO ENGAGE SAID PICKER STICK, ANOTHER ROLLER CARRIED BY SAID MOBILE STOP AND ENGAGING SAID CAM-SHAPED END, AND A SPRING CONNECTED WITH SAID MOBILE STOP AND PRESSING THE SECONDMENTIONED ROLLER AGAINST SAID CAM-SHAPED END, SAID CAM AND SAID CAM-SHAPED END BEING SHAPED SO THAT A SMALL ANGULAR DISPLACEMENT OF SAID CAM GIVES RISE TO A LARGER ANGULAR DISPLACEMENT OF SAID CAM-SHAPED END. 